Hitherto, there is known an information recording apparatus that records information in a portable type of recording medium, for example, CD and DVD, and the improvement of storage capacity in such a portable type of recording medium becomes an important problem with the development of the digital technique and the information technology in recent years so far.
As one of the technologies for implementing a large storage capacity in a portable type of recording medium, there is proposed a holographic recording apparatus that records information in the medium (holographic memory) by using the technology of the hologram (For instance, refer to Japanese patent document 1: Japanese Patent Laid Open Gazette TokuKai. 2000-89650). According to this holographic recording apparatus, it is considered that a very large capacity of recording, for instance 200 GB, can be implemented with one recording medium in such a way that the information light and the reference light interfere with one another on the medium and the interference is recorded in the medium.
In order to implement a large capacity of recording with such a holographic recording apparatus, it is necessary that as the reference light used for the information recording, two or more sorts of reference lights, which are different from one another in incident angle, wavelength, and phase, are used, and information is recorded on a multiple basis by the reference light of two or more kinds in the same part in the medium. A capacity of medium is determined by a recording area and a multiple number. In the use of the recording medium, it is necessary to use it in accordance with the specifications of the multiple numbers provided by the standard beforehand (It is called a multiple number of specifications).
However, regarding also the recording medium such as conventional CD and DVD, it often happens that non-standard goods that do not meet the specification of the standard are done the manufacturing sales and circulate. It is thought that such non-standard goods might circulate about the holographic memory too. Moreover, even in case of the medium that meets the specification of the standard when manufacturing it, it might not meet the specification of the standard by an unexpected exposure and the like after selling.
The use of the holographic memories of the specification shortages as mentioned above in the conventional holographic recording apparatus brings about a problem that the recording error of data is caused and reliability decreases, and also a problem that the existing data is destroyed by a multiple record. Those problems are very serious problems in connection with a matter that the holographic memory is especially for a large capacity.